#!/bin/sh
#Convert PDFs to show a specific number of input pages per output page
#Uses pdflatex with pdfpages package
#Will not accept filenames starting with a dash
#Warning: is vulnerable to LaTeX injection attack and does no checking

filenum=0

#LaTeX header
LaTeXDoc="\documentclass[letterpaper]{article}
\usepackage[letterpaper,pdftex]{geometry}
\usepackage{pdfpages}
\begin{document}
"

#Parameter defaults
pages="-"
nup="1x2"
angle="90"
error=""
command="$0"

#Get temporary working space
tempdir="`mktemp`"
tempfile="$tempdir/a.tex"

rm "$tempdir"
mkdir "$tempdir"

while [ -z "$error" -a "$#" -gt 0 ]
do
  param="$1"
  shift
  case "$param" in
    "-1")
      nup="1x1"
      angle="0"
    ;;

    "-2")
      nup="1x2"
      angle="90"
    ;;

    "-4")
      nup="2x2"
      angle="0"
    ;;

    "-6")
      nup="2x3"
      angle="0"
    ;;

    "--nup")
      nup="$1"
      shift
    ;;

    "--angle")
      angle="$1"
      shift
    ;;

    "--pages")
      pages="$1"
      shift
    ;;

    -*)
      error="Unknown parameter \"${param}\""
    ;;

    #Default is the filename
    *)
      filename="$param"
      if [ \! -f "$filename" ]
      then
        error="Cannot find file \"$filename\"."
      else
        cp "$filename" "${tempdir}/$((++filenum)).pdf"
        LaTeXDoc="${LaTeXDoc}
\includepdf[pages=$pages, nup=$nup, angle=$angle, frame=false, fitpaper=false, trim=0 0 0 0, delta=0 0, offset=0 0, scale=1.0, turn=true, noautoscale=false, column=false, columnstrict=false, openright=false]{${filenum}.pdf}"
      fi
    ;;

  esac

done

if [ "$filenum" = 0 ]
then
  error="You must specify a PDF file."
fi

if [ -n "$error" ]
then
  echo "${error}

pdfnup puts multiple pages of PDFs together on a page into a file named out.pdf.

Proper usage:
  pdfnup [-(1|2|4|6)] [--nup <X>x<Y>] [--angle <rotation>]
    [--pages <which pages>] <input pdf 1>
    [[more options...] <input pdf 2> [...]]

Examples:
  $command -2 data.pdf                             #Put 2 per page
  $command --nup 1x2 --angle 90 --pages - data.pdf #Equivalent to -2
  $command -4 --pages 3-7 data.pdf                 #2x2 per page of pages 3-7
  $command -1 data.pdf                             #Put 1 on letter paper
  $command -1 1.pdf 2.pdf                          #Concatenate 1 and 2
  $command -2 1.pdf -4 2.pdf       #Put 2x1 of 1 followed by 2x2 of 2
  $command -1 1.pdf 2.pdf ;                        #Combine 1.pdf and 2.pdf as
    mv out.pdf in.pdf ;                            #2x1 without skipping pages
    $command -2 in.pdf                             #in between PDFs
" > /dev/stderr
  exit 1
fi

LaTeXDoc="${LaTeXDoc}
\end{document}"

echo "$LaTeXDoc" > "$tempfile"


pushd "$tempdir" > /dev/null
pdflatex "$tempfile" < /dev/null > /dev/null 2> /dev/null
if [ "$?" \!= 0 ]
then
  error="Error processing PDF"
fi

popd > /dev/null
mv "$tempdir"/a.pdf out.pdf
if [ "$?" \!= 0 ]
then
  error="Can't move file"
fi

rm -r "$tempdir"

if [ -n "$error" ]
then
  echo "$error"
  exit 1
fi

echo "out.pdf created"